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Java Hash Set


What are Hash Sets ?

Java HashSet class is used to create a collection that uses a hash table for storage. Sets are used to remove duplicate elements from the list and that's the big advantage of Sets over List.

The important points about Java HashSet class are:

HashSet stores the elements by using a mechanism called hashing.

HashSet contains unique elements only.

Difference between List and Set

List can contain duplicate elements whereas Set contains unique elements only.

Example :-

import java.util.*;

public class JavaHashSetsDemo {
  public static void main(String[] args)
  {
    String[] things = {"Apples","Mango","Strwaberry","Mango"};
    List list = Arrays.asList(things);
    
    System.out.printf("%s ", list);
    System.out.println();
    
    Set set = new HashSet(list);
    System.out.printf("%s ", set);
  }
  
}

Output :-

[Apples, Mango, Strwaberry, Mango] 
[Apples, Strwaberry, Mango]